runflat tire and it‘s impact on biax testing · 2020-03-15 · said allouch application...
TRANSCRIPT
© Fraunhofer LBF
13th Users Conference on BiAxial Fatigue Testing
November 08th, 2017
Dipl. Ing. Said Allouch Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF www.lbf.fraunhofer.de
Runflat tire and it‘s impact on BiAx Testing
© Fraunhofer LBF
Page 2
Relevance of tires
With regard to vehicle dynamics the tire is the basic load transfer element
The usage of the tire in the biax testing make this technology near to the reality
development in the field of tire technology do show a clear trend towards runflat
Runflat different build up different behavior regarding the durability
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Possible impacts of Tires Test
External wheel loads on the
road
Internal wheel stresses on the road/LBF flat
track
Internal wheel stresses during
testing
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Differences of physical characteristics Run Flat vs. Standard Tire – vertical stiffness –
The vertical stiffness of run flat tires is 33% higher than the stiffness of standard tires
The lower the vertical stiffness of a tire, the lower the occurring vertical loads
Jeschor, M.: Ein neues Verfahren zur Bewertung von Runflat-Reifen – ein
Beitrag auf dem Weg zum reserveradlosen PKW; Diss. TU Dresden, 2005
© Fraunhofer LBF
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Differences of physical characteristics Run Flat vs. Standard Tire – lateral stiffness –
The lateral stiffness of run flat tires is higher than the lateral stiffness of standard tires which cause better handling properties
This difference has also an effect on the external loads and the transmission of the loads into the wheel
Jeschor, M.: Ein neues Verfahren zur Bewertung von Runflat-Reifen – ein
Beitrag auf dem Weg zum reserveradlosen PKW; Diss. TU Dresden, 2005
© Fraunhofer LBF
Page 6
Chosen tires of the investigation
Tire size 225/45 R17
Wheel size 7.0 x 17
tire abbreviation
Bridgestone Turanza BT
Bridgestone Turanza MOE BT MOE
Bridgestone Turanza RFT BT RFT
Michelin Primacy 3 ZP MP
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Impact on external loads Used test vehicle
Tire size 225/45 R17
Wheel size 7.0 x 17
7x17
RoaDynET = 66,4mm
Lochkreis : 5x112
Zentrierung: 57 mm
Radbolzen M14x1,5 mit 90° Kegel
Max. Länge ab Konus Beginn 53mm
Min. Länge ab Konus Beginn 40mm
Beste Länge ab Konus 45-50mm
Bereifung: 215/50 R17
Opel Astra J 103 kW
Static load = 500 kg
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Impact on external loads Measurement tracks (Dudenhofen)
Durability
Cornering
Rough road
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Impact on external loads Tire positions during RLDA
A
BT BT RFT
BT MOE
MP
B
BT
MP BT
RFT
C
MP BT
MOE
BT
RFT BT
D
BT
RFT MP
BT BT
MOE
4 different wheel positions were measured with the same tire and manoever
the wheels swaped places in clockwise rotation
Air pressure of all tires: 2,7 bar
Tire temperature: comparable on each measurement
Bolting torque (wheel bolt) : 120 Nm
BT
MOE
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Impact on external loads Tire positions during RLDA
A
BT BT RFT
BT MOE
MP
B
BT
MP BT
RFT
C
MP BT
MOE
BT
RFT BT
BT
MOE
D
BT
RFT MP
BT BT
MOE
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Impact on external loads Results (rough road)
-200%
-150%
-100%
-50%
0%
50%
100%
150%
BT BT MOE BT RFT MP
Fh
[k
N]
80%
85%
90%
95%
100%
105%
110%
115%
120%
125%
130%
BT BT MOE BT RFT MP
Fv
[k
N]
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Impact on external loads Results (cornering)
80%
85%
90%
95%
100%
105%
110%
BT BT MOE BT RFT MP
Fh
[k
N]
80%
90%
100%
110%
120%
130%
140%
BT BT MOE BT RFT MPFv
[k
N]
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Impact on external loads Results (lateral forces spectra comparison)
Range pair
Late
ral f
orc
e [
kN
]
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Range pair
Impact on external loads Results (vertical forces spectra comparison)
Ve
rtic
al fo
rce
[kN
]
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Impact of the runflat tire on the internal stresses LBF Flat track roll rig
Fv [kN] Fh [kN]
Static load 5,0 0
Straight driving incl. rough road 13,90 +/-3,50
Cornering 9,04 6,66
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0
5
10
15
20
25
under static load straight driving cornering
Am
pli
tud
e [
MP
a]
inner rim flange
0
5
10
15
20
25
under static load straight driving cornering
Am
pli
tud
e [
MP
a]
inner spoke transition to the rim
0
10
20
30
40
50
under static load straight driving cornering
Am
pli
tud
e [
MP
a]
inner mid of spoke
Impact of the runflat tire on the internal stresses Results I
17%
14%
18%
13%
15% 10%
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0
5
10
15
20
25
30
35
40
45
under static load straight driving cornering
Am
pli
tud
e [
MP
a]
inner spoke transition to the bolting area
0
5
10
15
20
25
30
35
40
45
50
under static load straight driving cornering
Am
pli
tud
e [
MP
a]
bolting area
0
5
10
15
20
25
30
35
40
under static load straight driving cornering
Am
pli
tud
e [
MP
a]
outer rim flange
Impact of the runflat tire on the internal stresses Results II
15%
17%
7%
7%
21%
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Load file: LBF standard
Tire inflation pressure: 4 MPa
Measurement of 1 loop -> extrapolation to 10,000 km
Impact of the runflat tire on the internal stresses LBF ZWARP machine
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Impact of the runflat tire on the internal stresses RFS results
80%
85%
90%
95%
100%
105%
110%
inner rim flange inner spoketransition to the rim
inner mid of spoke inner spoketransition to the
bolting area
bolting area outer rim flange
no
rma
lize
d
RFS
v
alu
es
RFS values comparison
BT
BT MOE
BT RFT
MP
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All parts of the process chain were investigated
External loads: Runflat tires have an impact on lateral and horizontal wheel loads -> RLDA needs to be performed with RFT
Internal stresses (LBF flat track roll rig): Runflat tires cause higher internal stresses by straight … -> ESA needs to be performed with RFT
Internal stresses (LBF ZWARP): Runflat tires cause small impact on local stresses -> Test is recommended to be performed with RFT
Different RFT were investigated, they performed different, a general impact was not given
Conclusions
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Contact
Fraunhofer Institute for Structural Durability and System Reliability LBF
Group Validation Wheel Related Components
Bartningstrasse 47, 64289 Darmstadt, Germany
Telefon: +49 6151 705-0, Fax: +49 6151 705-214
www.lbf.fraunhofer.de, www.zwarp.de
Said Allouch
Application specialist passenger cars